PSEP: 1

Title: PSEP Purpose and Guidelines

Version: $Revision$

Last-Modified: $Date$

Author: Matti Airas

Status: Active

Type: Process

Content-Type: text/x-rst

Created: 23-Sep-2009

What is a PSEP?

===============

PSEP stands for PySide Enhancement Proposal.  A PSEP is a design

document providing information to the PySide community, or describing

a new feature for PySide or its processes or environment.  The PSEP

should provide a concise technical specification of the feature and a

rationale for the feature.

We intend PSEPs to be the primary mechanisms for proposing new

features, for collecting community input on an issue, and for

documenting the design decisions that have gone into PySide.  The PSEP

author is responsible for building consensus within the community and

documenting dissenting opinions.

Because the PSEPs are maintained as text files in a versioned

repository, their revision history is the historical record of the

feature proposal [1]_.

The whole PSEP process has been copied verbatim from Python's PEP

(Python Enhancement Proposal) process, and this document has been

adapted to PSEP by Matti Airas from PEP 1 by Barry Warsaw, Jeremy

Hylton, and David Goodger.

PSEP Types

==========

There are three kinds of PSEP:

1. A **Standards Track** PSEP describes a new feature or implementation

   for PySide.

2. An **Informational** PSEP describes a PySide design issue, or

   provides general guidelines or information to the PySide community,

   but does not propose a new feature.  Informational PSEPs do not

   necessarily represent a PySide community consensus or

   recommendation, so users and implementors are free to ignore

   Informational PSEPs or follow their advice.

3. A **Process** PSEP describes a process surrounding PySide, or

   proposes a change to (or an event in) a process.  Process PSEPs are

   like Standards Track PSEPs but apply to areas other than the PySide

   itself.  They may propose an implementation, but not to

   PySide's codebase; they often require community consensus; unlike

   Informational PSEPs, they are more than recommendations, and users

   are typically not free to ignore them.  Examples include

   procedures, guidelines, changes to the decision-making process, and

   changes to the tools or environment used in Python development.

   Any meta-PSEP is also considered a Process PSEP.

PSEP Work Flow

==============

The PSEP editors assign PSEP numbers and change their status.  The

current PSEP editor is Matti Airas.  Please send

all PSEP-related email to <pyside@lists.openbossa.org> (no cross-posting please).

Also see `PSEP Editor Responsibilities & Workflow`_ below.

The PSEP process begins with a new idea for PySide.  It is highly

recommended that a single PSEP contain a single key proposal or new

idea.  The more focussed the PSEP, the more successful it tends to

be.  The PSEP editor reserves the right to reject PSEP proposals if they

appear too unfocussed or too broad.  If in doubt, split your PSEP into

several well-focussed ones.

Each PSEP must have a champion -- someone who writes the PSEP using the

style and format described below, shepherds the discussions in the

appropriate forums, and attempts to build community consensus around the

idea.  The PSEP champion (a.k.a. Author) should first attempt to

ascertain whether the idea is PSEP-able.  Posting to the

pyside@lists.openbossa.org mailing list is recommended.  Enhancements not

resulting in API changes usually don't need a PSEP and can be injected

into the PySide development work flow with a patch submission to the

PySide `issue tracker`_.

The PSEP champion then emails the PSEP editor <pyside@lists.openbossa.org> with a

proposed title and a rough, but fleshed out, draft of the PSEP.  This

draft must be written in PSEP style as described below.

If the PSEP editor approves, he will assign the PSEP a number, label it

as Standards Track, Informational, or Process, give it status "Draft",

and create and check-in the initial draft of the PSEP.  The PSEP editor

will not unreasonably deny a PSEP.  Reasons for denying PSEP status

include duplication of effort, being technically unsound, not providing

proper motivation or addressing backwards compatibility, or not in

keeping with the PySide philosophy.  The TBC (Temporary Benevolent

Committee, consisting of the core dev team and Matti Airas) can be consulted

during the approval phase, and is the final arbiter of the draft's

PSEP-ability.

If a pre-PSEP is rejected, the author may elect to take the pre-PSEP to

the pyside@lists.openbossa.org mailing list to help flesh it out, gain feedback

and consensus from the community at large, and improve the PSEP for

re-submission.

The author of the PSEP is then responsible for posting the PSEP to the

community forums, and marshaling community support for it.  As updates

are necessary, the PSEP author can check in new versions if they have

SVN commit permissions, or can email new PSEP versions to the PSEP

editor for committing.

Standards Track PSEPs consist of two parts, a design document and a

reference implementation.  The PSEP should be reviewed and accepted

before a reference implementation is begun, unless a reference

implementation will aid people in studying the PSEP.  Standards Track

PSEPs must include an implementation -- in the form of code, a patch,

or a URL to same -- before it can be considered Final.

PSEP authors are responsible for collecting community feedback on a PSEP

before submitting it for review.  A PSEP that has not been discussed on

pyside@lists.openbossa.org will not be

accepted.  However, wherever possible, long open-ended discussions on

public mailing lists should be avoided.  Strategies to keep the

discussions efficient include: setting up a separate SIG mailing list

for the topic, having the PSEP author accept private comments in the

early design phases, setting up a wiki page, etc.  PSEP authors should

use their discretion here.

Once the authors have completed a PSEP, they must inform the PSEP editor

that it is ready for review.  PSEPs are reviewed by the TBC, who may

accept or reject a PSEP or send it back to the author(s) for revision.

For a PSEP that is pre-determined to be acceptable (e.g., it is an

obvious win as-is and/or its implementation has already been checked in)

the TBC may also initiate a PSEP review, first notifying the PSEP

author(s) and giving them a chance to make revisions.

For a PSEP to be accepted it must meet certain minimum criteria.  It

must be a clear and complete description of the proposed enhancement.

The enhancement must represent a net improvement.  The proposed

implementation, if applicable, must be solid and must not complicate the

interpreter unduly.  Finally, a proposed enhancement must properly

balance the "pythonicity" and "Qt-likeness" in order to be accepted by

the TBC.  (However, "pythonic" and "Qt-likeness" are imprecise terms;

they may be defined as whatever is acceptable to the TBC.  This logic is

intentionally circular.)

Once a PSEP has been accepted, the reference implementation must be

completed.  When the reference implementation is complete and accepted

by the TBC, the status will be changed to "Final".

A PSEP can also be assigned status "Deferred".  The PSEP author or

editor can assign the PSEP this status when no progress is being made

on the PSEP.  Once a PSEP is deferred, the PSEP editor can re-assign it

to draft status.

A PSEP can also be "Rejected".  Perhaps after all is said and done it

was not a good idea.  It is still important to have a record of this

fact.

PSEPs can also be replaced by a different PSEP, rendering the original

obsolete.  This is intended for Informational PSEPs, where version 2 of

an API can replace version 1.

The possible paths of the status of PSEPs are as follows:

.. image:: psep-0001-1.png

Some Informational and Process PSEPs may also have a status of "Active"

if they are never meant to be completed.  E.g. PSEP 1 (this PSEP).

What belongs in a successful PSEP?

==================================

Each PSEP should have the following parts:

1. Preamble -- RFC 822 style headers containing meta-data about the

   PSEP, including the PSEP number, a short descriptive title (limited

   to a maximum of 44 characters), the names, and optionally the

   contact info for each author, etc.

2. Abstract -- a short (~200 word) description of the technical issue

   being addressed.

3. Copyright/public domain -- Each PSEP must either be explicitly

   labelled as placed in the public domain (see this PSEP as an

   example) or licensed under the `Open Publication License`_.

4. Specification -- The technical specification should describe the

   syntax and semantics of any new API feature.  The

   specification should be detailed enough to allow competing,

   interoperable implementations for any of the current Python Qt

   bindings.

5. Motivation -- The motivation is critical for PSEPs that want to

   change the PySide API.  It should clearly explain why the

   existing API is inadequate to address the

   problem that the PSEP solves.  PSEP submissions without sufficient

   motivation may be rejected outright.

6. Rationale -- The rationale fleshes out the specification by

   describing what motivated the design and why particular design

   decisions were made.  It should describe alternate designs that

   were considered and related work, e.g. how the feature is supported

   in other languages.

   The rationale should provide evidence of consensus within the

   community and discuss important objections or concerns raised

   during discussion.

7. Backwards Compatibility -- All PSEPs that introduce backwards

   incompatibilities must include a section describing these

   incompatibilities and their severity.  The PSEP must explain how the

   author proposes to deal with these incompatibilities.  PSEP

   submissions without a sufficient backwards compatibility treatise

   may be rejected outright.

8. Reference Implementation -- The reference implementation must be

   completed before any PSEP is given status "Final", but it need not

   be completed before the PSEP is accepted.  It is better to finish

   the specification and rationale first and reach consensus on it

   before writing code.

   The final implementation must include test code and documentation

   appropriate for either the PySide API reference or the respective

   generator tool reference.

PSEP Formats and Templates

==========================

As opposed to PEP, there is only one PSEP format available to authors:

reStructuredText_.  ReStructuredText_ PSEPs allow for rich markup that

is still quite easy to read, but results in much better-looking and more

functional HTML.  PSEP 12 contains instructions and a template [2]_ for

reStructuredText PSEPs.

There is a Python script that converts PSEPs to HTML for

viewing on the web [3]_.  reStructuredText PSEPs are parsed

and converted by Docutils_ code called from the script.

PSEP Header Preamble

====================

Each PSEP must begin with an RFC 822 style header preamble.  The headers

must appear in the following order.  Headers marked with "*" are

optional and are described below.  All other headers are required. ::

    PSEP: <psep number>

    Title: <psep title>

    Last-Modified: <svn date string>

    Author: <list of authors' real names and optionally, email addrs>

  * Discussions-To: <email address>

    Status: <Draft | Active | Accepted | Deferred | Rejected |

             Withdrawn | Final | Replaced>

    Type: <Standards Track | Informational | Process>

  * Content-Type: <text/plain | text/x-rst>

  * Requires: <psep numbers>

    Created: <date created on, in dd-mmm-yyyy format>

  * Python-Version: <version number>

    Post-History: <dates of postings to python-list and python-dev>

  * Replaces: <psep number>

  * Replaced-By: <psep number>

The Author header lists the names, and optionally the email addresses

of all the authors/owners of the PSEP.  The format of the Author header

value must be

    Random J. User <address@dom.ain>

if the email address is included, and just

    Random J. User

if the address is not given.  New PSEPs must use the mandated format

above.

If there are multiple authors, each should be on a separate line

following RFC 2822 continuation line conventions.  Note that personal

email addresses in PSEPs will be obscured as a defense against spam

harvesters.

While a PSEP is in private discussions (usually during the initial

Draft phase), a Discussions-To header will indicate the mailing list

or URL where the PSEP is being discussed.  No Discussions-To header is

necessary if the PSEP is being discussed privately with the author, or

on the pyside@lists.openbossa.org mailing list.  Note that email

addresses in the Discussions-To header will not be obscured.

The Type header specifies the type of PSEP: Standards Track,

Informational, or Process.

The format of a PSEP is specified with a Content-Type header.  The only

acceptable values is "text/x-rst" for reStructuredText PSEPs (see PSEP

12 [2]_).

The Created header records the date that the PSEP was assigned a

number, while Post-History is used to record the dates of when new

versions of the PSEP are posted to python-list and/or python-dev.  Both

headers should be in dd-mmm-yyyy format, e.g. 14-Aug-2001.

TODO: How should we deal with different Python, Qt, and PySide versions?

*Standards Track PSEPs must have a Python-Version header which indicates

the version of Python that the feature will be released with.

Informational and Process PSEPs do not need a Python-Version header.*

PSEPs may have a Requires header, indicating the PSEP numbers that this

PSEP depends on.

PSEPs may also have a Replaced-By header indicating that a PSEP has been

rendered obsolete by a later document; the value is the number of the

PSEP that replaces the current document.  The newer PSEP must have a

Replaces header containing the number of the PSEP that it rendered

obsolete.

Auxiliary Files

===============

PSEPs may include auxiliary files such as diagrams.  Such files must be

named ``psep-XXXX-Y.ext``, where "XXXX" is the PSEP number, "Y" is a

serial number (starting at 1), and "ext" is replaced by the actual

file extension (e.g. "png").

Reporting PSEP Bugs, or Submitting PSEP Updates

===============================================

How you report a bug, or submit a PSEP update depends on several

factors, such as the maturity of the PSEP, the preferences of the PSEP

author, and the nature of your comments.  For the early draft stages

of the PSEP, it's probably best to send your comments and changes

directly to the PSEP author.  For more mature, or finished PSEPs you may

want to submit corrections to the PySide `issue tracker`_ so that your

changes don't get lost.  If the PSEP author is a PySide developer, assign the

bug/patch to him, otherwise assign it to the PSEP editor.

When in doubt about where to send your changes, please check first

with the PSEP author and/or PSEP editor.

PSEP authors who have write permissions to the Gitorious repository can

push the changes to the repository themselves.

Transferring PSEP Ownership

===========================

It occasionally becomes necessary to transfer ownership of PSEPs to a

new champion.  In general, we'd like to retain the original author as

a co-author of the transferred PSEP, but that's really up to the

original author.  A good reason to transfer ownership is because the

original author no longer has the time or interest in updating it or

following through with the PSEP process, or has fallen off the face of

the 'net (i.e. is unreachable or not responding to email).  A bad

reason to transfer ownership is because you don't agree with the

direction of the PSEP.  We try to build consensus around a PSEP, but if

that's not possible, you can always submit a competing PSEP.

If you are interested in assuming ownership of a PSEP, send a message

asking to take over, addressed to both the original author and the PSEP

editor <pyside@lists.openbossa.org>.  If the original author doesn't respond to

email in a timely manner, the PSEP editor will make a unilateral

decision (it's not like such decisions can't be reversed :).

PSEP Editor Responsibilities & Workflow

=======================================

A PSEP editor must subscribe to the <pyside@lists.openbossa.org> list.  All

PSEP-related correspondence should be sent (or CC'd) to

<pyside@lists.openbossa.org> (but please do not cross-post!).

For each new PSEP that comes in an editor does the following:

* Read the PSEP to check if it is ready: sound and complete.  The ideas

  must make technical sense, even if they don't seem likely to be

  accepted.

* The title should accurately describe the content.

* Edit the PSEP for language (spelling, grammar, sentence structure,

  etc.), markup (for reST PSEPs), code style (examples should match PSEP

  8 & 7).

If the PSEP isn't ready, the editor will send it back to the author for

revision, with specific instructions.

Once the PSEP is ready for the repository, the PSEP editor will:

* Assign a PSEP number (almost always just the next available number,

  but sometimes it's a special/joke number, like 666 or 3141).

* List the PSEP in PSEP 0 (in two places: the categorized list, and the

  numeric list).

* Add the PSEP to the Git repository. To clone a copy of the Git

  repository, see `the PySide Gitorious page

  <http://qt.gitorious.org/pyside>`_.

* Monitor python.org to make sure the PSEP gets added to the site

  properly.

* Send email back to the PSEP author with next steps (post to

  pyside@lists.openbossa.org).

Updates to existing PSEPs also come in to pyside@lists.openbossa.org.

Alternatively, Gitorious merge requests may be made directly.

Many PSEPs are written and maintained by developers with write access to

the PySide repository.  The PSEP editors monitor the repository PSEP

changes, and correct any structure, grammar, spelling, or markup

mistakes we see.

The editors don't pass judgement on PSEPs.  We merely do the

administrative & editorial part.  Except for times like this, there's

relatively low volume.

References and Footnotes

========================

.. [1] This historical record is available by the normal Git commands

   for retrieving older revisions.  For those without direct access to

   the Git tree, you can browse the current and past PSEP revisions here:

   http://qt.gitorious.org/pyside/pseps

.. [2] PEP 12, Sample reStructuredText PSEP Template, Goodger, Warsaw

   (http://www.python.org/dev/peps/pep-0012)

.. [3] The script referred to here is pep2pyramid.py, the successor to

   pep2html.py, both of which live in the same directory in the Git

   tree as the PEPs themselves.  Try ``pep2html.py --help`` for

   details.  The URL for viewing PEPs on the web is

   http://www.python.org/dev/peps/.

.. _issue tracker:

   http://bugs.openbossa.org/

.. _Open Publication License: http://www.opencontent.org/openpub/

.. _reStructuredText: http://docutils.sourceforge.net/rst.html

.. _Docutils: http://docutils.sourceforge.net/

Copyright

=========

This document has been placed in the public domain.

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